Comparison of Ti, Zr, and Hf as Cations for Metallocene-Catalyzed Olefin Polymerization

• Published in: Organometallics Vol. 25; no. 19; pp. 4483 - 4490
• Main Authors: Silanes, Iñaki, Mercero, Jose M, Ugalde, Jesus M
• Format: Journal Article
• Language: English
• Published: American Chemical Society 11-09-2006
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/om050790r

In this paper we make use of a carefully chosen counterion model, B(CF2Cl)3, for a molecularly well-defined metallocenic catalyst counterion, B(C6F5)3, to perform a comparison of Cp2M(CH3)2-type metallocene activities toward ethylene polymerization, for M = Ti, Zr, and Hf. Monomer complexation and chain-insertion barriers are calculated and discussed, and a higher intrinsic activity for titanium is derived. Calculations are also performed in order to add further evidence of the suitability of the counterion model used. We conclude that the model employed here can act as an accurate enough substitute for the original borate in quantum mechanical calculations.